Select the true statement: a. an emergency plan should be reviewed and updated at least every 1 or 2 years and after key events, including plan activation. b. an emergency plan is considered up-to-date if it has been reviewed at least once in the last decade. c. an emergency plan only needs to be updated when there is a revision in the laws, codes, or ordinances that govern emergency planning. d. the best time to review and update an emergency plan is during a major activation of the plan, while personnel are focused on the policies and procedures.